Tiko, Don't delete your cooler. That wasnt the suggestion. What you DO want, is the return from the HB to go directly to the top return port on the pump. You want as little back pressure as possible on the HB return. The return from the steering box should go through your cooler and to the bottom return port on the pump.
I have a astrovan HB I installed on my 75 F250 with saginaw pump and 35's , my steering is 1 finger while parked and the braking is very impressive. You'll get there.